Black iron gas pipe and fittings are relatively inexpensive, strong, and modular, which can make them ideal for fabricating sturdy props and mounts. The parts are readily available at any hardware store.
This rack is optional -- you may use a normal test tube rack if you like -- but either way, it helps to have a rack before you begin mixing your potion and filling the test tubes!
Screw two of the 8" pipe nipples into the floor flanges.
Screw two of the pipe couplings onto the two pipe nipples that have been screwed into the flanges.
Use the CAD file linked below to laser cut the acrylic rack shelves and support. Alternately, you may print the file and use it as a template to cut the rack with a scroll saw.
Screw one locknut onto each end of the remaining two 8" pipe nipples. Set the bottom rack shelf onto the bottom ends of the pipe nipples and then thread these into the pipe fittings.
Place the acrylic support that will hold the Feather into the base and top shelves, fitting its pointed end into the square cutout.
Create the crossbar by joining the two 6" pipe nipples with the remaining coupling, then screw their free ends into the elbows.
Place the top shelf over the leg threads, being sure to line up the vertical support with the square cutout, and then screw the legs into the elbows.
To stabilize the rack, you can screw the flanges into a wooden base.